Effect of stocking density and alpha-lipoic acid on the growth performance, physiological and oxidative stress and immune response of broilers

Objective: The study was conducted to evaluate the effect of stocking density and alphalipoic acid (ALA) on the growth performance, feed utilization, carcass traits, antioxidative ability and immune response of broilers. Methods: A total of 1,530 22-day-old male broilers (Arbor Acres) with comparable body weights ($731.92{\pm}5.26$) were placed into 18 cages ($2.46{\times}2.02m$) in groups of 75 birds ($15birds/m^2$, $37.5kg/m^2$; low stocking density [LD]), 90 birds ($18birds/m^2$, $45.0kg/m^2$; high stocking density [HD]) and 90 birds with 300 mg/kg ALA added to the basal diet ($18birds/m^2$, $45.0kg/m^2$; HD+ALA, high stocking density+${\alpha}$-lipoic acid); each treatment was represented by 6 replicates. The experimental period was 3 weeks. Results: The results showed that the high stocking density regimen resulted in a decreased growth, feed conversion ratio, carcass weight, thigh yield and bursa weight relative to body weight (p